Base station device, terminal device, wireless communication system, and wireless communication method

ABSTRACT

A base station device that allocates wireless resources to a terminal device and performs wireless communication with the terminal device using the allocated wireless resources, the base station device includes, deciding controller that decides, out of a plurality of retransmission patterns, a retransmission pattern for performing retransmission of data to the terminal device, in accordance with a communication state of wireless communication, and a transmitter that performs initial-time transmission processing of transmitting a control signal for wireless resource allocation control, and a data signal for data transmission including data to be transmitted to the terminal device, including retransmission pattern information relating to the retransmission pattern that has been decided, and retransmission processing of retransmitting the data signal including data to be transmitted to the terminal device, in accordance with the retransmission pattern that has been decided.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation application of U.S. application Ser.No. 16/992,987 filed on Aug. 13, 2020, which is a continuationapplication of International Application No. PCT/JP2018/005192 filed onFeb. 15, 2018, and designated the U.S., the entire contents of each areincorporated herein by reference.

FIELD

The present invention relates to a base station device, a terminaldevice, a wireless communication system, and a wireless communicationmethod.

BACKGROUND

Mobile terminal (e.g., smartphone and future phone) traffic currentlytakes up the greater part of network resources. Traffic used by mobileterminals also is in a trend of expanding.

On the other hand, there is demand for networks to handle services withvarious requirement conditions, as IoT (Internet of a things) services(e.g., traffic systems, smart meters, monitoring systems of devices andso forth) are being implemented. Accordingly, technology for realizingeven greater high data rates, large capacity, and low latency isdemanded in the 5th generation mobile communication systems (5G, or NR(New Radio)) communication standard, in addition to the standardtechnology of 4G (4th generation mobile communication systems).

5G anticipates supporting many usage cases classified into, for example,eMBB (Enhanced Mobile BroadBand), Massive MTC (Machine TypeCommunications), and URLLC (Ultra-Reliable and Low LatencyCommunication), to handle a wide variety of services as described above.

Realization of URLLC, which is one of the usage cases, is difficult.High reliability is demanded of URLLC, and a lower wireless portionerror rate than conventionally realized is demanded. One method ofrealizing ultra-high reliability is to increase the amount of resourcesused, and impart redundancy to the data. However, wireless resources arelimited, and are not endlessly increasable.

Also, low latency demands in URLLC are that uplink and downlink userplane wireless portion latency be lower values than in a 4G network, forexample.

URLLC has to satisfy the two requests of ultra-high reliability and lowlatency at the same time, as described above.

Technology regarding URLLC is described in the following literature.

CITATION LIST Non-Patent Literature

-   -   NON PATENT LITERATURE 1: 3GPP TS 36.211 V15.0.0 (December 2017)    -   NON PATENT LITERATURE 2: 3GPP TS 36.212 V15.0.1 (January 2018)    -   NON PATENT LITERATURE 3: 3GPP TS 36.213 V15.0.0 (December 2017)    -   NON PATENT LITERATURE 4: 3GPP TS 36.300 V15.0.0 (December 2017)    -   NON PATENT LITERATURE 5: 3GPP TS 36.321 V15.0.0 (December 2017)    -   NON PATENT LITERATURE 6: 3GPP TS 36.322 V15.0.0 (December 2017)    -   NON PATENT LITERATURE 7: 3GPP TS 36.323 V14.5.0 (December 2017)    -   NON PATENT LITERATURE 8: 3GPP TS 36.331 V15.0.1 (January 2018)    -   NON PATENT LITERATURE 9: 3GPP TS 36.413 V15.0.0 (December 2017)    -   NON PATENT LITERATURE 10: 3GPP TS 36.423 V15.0.0 (December 2017)    -   NON PATENT LITERATURE 11: 3GPP TS 36.425 V14.0.0 (March 2017)    -   NON PATENT LITERATURE 12: 3GPP TS 37.340 V15.0.0 (December 2017)    -   NON PATENT LITERATURE 13: 3GPP TS 38.201 V15.0.0 (December 2017)    -   NON PATENT LITERATURE 14: 3GPP TS 38.202 V15.0.0 (December 2017)    -   NON PATENT LITERATURE 15: 3GPP TS 38.211 V15.0.0 (December 2017)    -   NON PATENT LITERATURE 16: 3GPP TS 38.212 V15.0.0 (December 2017)    -   NON PATENT LITERATURE 17: 3GPP TS 38.213 V15.0.0 (December 2017)    -   NON PATENT LITERATURE 18: 3GPP TS 38.214 V15.0.0 (December 2017)    -   NON PATENT LITERATURE 19: 3GPP TS 38.215 V15.0.0 (December 2017)    -   NON PATENT LITERATURE 20: 3GPP TS 38.300 V15.0.0 (December 2017)    -   NON PATENT LITERATURE 21: 3GPP TS 38.321 V15.0.0 (December 2017)    -   NON PATENT LITERATURE 22: 3GPP TS 38.322 V15.0.0 (December 2017)    -   NON PATENT LITERATURE 23: 3GPP TS 38.323 V15.0.0 (December 2017)    -   NON PATENT LITERATURE 24: 3GPP TS 38.331 V15.0.0 (December 2017)    -   NON PATENT LITERATURE 25: 3GPP TS 38.401 V15.0.0 (December 2017)    -   NON PATENT LITERATURE 26: 3GPP TS 38.410 V 0.6.0 (December 2017)    -   NON PATENT LITERATURE 27: 3GPP TS 38.413 V0.5.0(December 2017)    -   NON PATENT LITERATURE 28: 3GPP TS 38.420 V0.5.0(December 2017)    -   NON PATENT LITERATURE 29: 3GPP TS 38.423 V0.5.0(December 2017)    -   NON PATENT LITERATURE 30: 3GPP TS 38.470 V15.0.0 (January 2018)    -   NON PATENT LITERATURE 31: 3GPP TS 38.473 V15.0.0 (December 2017)    -   NON PATENT LITERATURE 32: 3GPP TR 38.801 V14.0.0(April 2017)    -   NON PATENT LITERATURE 33: 3GPP TR 38.802 V14.2.0(September 2017)    -   NON PATENT LITERATURE 34: 3GPP TR 38.803 V14.2.0(September 2017)    -   NON PATENT LITERATURE 35: 3GPP TR 38.804 V14.0.0 (March 2017)    -   NON PATENT LITERATURE 36: 3GPP TR 38.900 V14.3.1 (July 2017)    -   NON PATENT LITERATURE 37: 3GPP TR 38.912 V14.1.0 (June 2017)    -   NON PATENT LITERATURE 38: 3GPP TR 38.913 V14.3.0 (June 2017)

However, there are cases where data transmitted from a base stationdevice to a terminal device does not arrive with predetermined quality,in situations where the wireless environment is poor, for example. Inthis case, low latency is not satisfied with data retransmissionoccurring and so forth. Also, for example, if the base station devicethat has transmitted data awaits an ACK (Acknowledgement) confirming thearrival of data or a NACK (Negative Acknowledgement) indicating thatdata did not arrive without error before retransmitting data, arrival ofdata to the terminal device is delayed even further, and there are caseswhere low latency is not realized.

SUMMARY

A base station device that allocates wireless resources to a terminaldevice and performs wireless communication with the terminal deviceusing the allocated wireless resources, the base station deviceincludes, deciding controller that decides, out of a plurality ofretransmission patterns, a retransmission pattern for performingretransmission of data to the terminal device, in accordance with acommunication state of wireless communication, and a transmitter thatperforms initial-time transmission processing of transmitting a controlsignal for wireless resource allocation control, and a data signal fordata transmission including data to be transmitted to the terminaldevice, including retransmission pattern information relating to theretransmission pattern that has been decided, and retransmissionprocessing of retransmitting the data signal including data to betransmitted to the terminal device, in accordance with theretransmission pattern that has been decided.

The object and advantages of the invention will be realized and attainedby means of the elements and combinations particularly pointed out inthe claims.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and arenot restrictive of the invention.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating a configuration example of a wirelesscommunication system 10.

FIG. 2 is a diagram illustrating a configuration example of the basestation device 200.

FIG. 3 is a diagram illustrating a configuration example of the terminaldevice 100.

FIG. 4 is a diagram illustrating an example of data retransmission bythe base station device 200 in a simple retransmission format.

FIG. 5 is a diagram illustrating an example of data retransmission tothe terminal device 100-1 in the simple retransmission format.

FIG. 6 is a diagram illustrating an example of a sequence in dataretransmission processing according to the new retransmission format.

FIG. 7 is a diagram illustrating an example of a processing flowchartfor the retransmission pattern deciding processing S101.

FIG. 8 is a diagram illustrating an example of a retransmission patterntable.

FIG. 9A to FIG. 9D are diagrams illustrating an example of aretransmission pattern where transmission timings and frequency bandsare changed to perform retransmission.

FIG. 10A to FIG. 10C are diagrams illustrating an example of aretransmission pattern where the frequency band is changed andretransmission is performed at the same transmission timing.

FIG. 11A to FIG. 11C are diagram illustrating examples of otherretransmission patterns.

FIG. 12 is a diagram illustrating an example of a sequence in dataretransmission processing according to the new retransmission format.

FIG. 13 is a diagram illustrating an example of a processing flowchartof the retransmission pattern control processing S203.

FIG. 14 is a diagram illustrating an example of a sequence of uplinkdata retransmission processing according to the new retransmissionformat.

DESCRIPTION OF EMBODIMENTS

The present embodiment will be described below in detail with referenceto the Figures. Objects and examples in the present specification areexemplary, and do not limit the scope of the present application.Particularly, the technology of the present application is applicableeven if expressions in the description are different, as long astechnologically equivalent, and different expressions do not limit thescope of the present application. The embodiments may be combined asappropriate within a scope where processing contents are notcontradictory.

Terms and technical content described in specifications andcontributions serving as standards relating to communication such as3GPP may be applied as appropriate to terms used in the presentspecification and technical content described therein. An example ofsuch a specification is 3GPP TS 38.300 V15.0.0 (December 2017).

Examples of the base station device, terminal device, wirelesscommunication system, and wireless communication method according to thedisclosure of the present application will be described below in detail,with reference to the Figures. Note that the following examples do notlimit the technology of the disclosure.

First Embodiment

In a first embodiment, a base station device decides a retransmissionpattern for retransmitting data to a terminal device in accordance witha communication state of wireless communication. The base station devicethen transmits, to a terminal device, control signals for control ofallocation of wireless resources including retransmission patterninformation regarding the retransmission pattern that has been decided,and data signals for data transmission including data to be transmittedto the terminal device. The base station device further retransmits datasignals including data to be transmitted to the terminal device, inaccordance with the retransmission pattern that has been decided.

Configuration Example of Wireless Communication System

FIG. 1 is a diagram illustrating a configuration example of a wirelesscommunication system 10. The wireless communication system 10 includesterminal devices 100-1 and 2, and a base station device 200. Thewireless communication system 10 is a wireless communication system thatconforms to a communication standard such as 4G, 5G, or the like, forexample.

The terminal devices 100-1 and 2 (hereinafter may be referred to asterminal device 100) are mobile communication terminals such assmartphones, tablet terminals, or the like, for example. The terminaldevice 100 wirelessly connects to the base station device 200 andcommunicates with an external network or another communication devicevia the base station device 200, for example. Note that the number ofthe terminal device 100 in the wireless communication system 10 may bethree or more.

The base station device 200 wirelessly connects to the terminal device100 and performs wireless communication with the terminal device 100.The base station device 200 also relays communication that the terminaldevice 100 performs with another communication device. The base stationdevice 200 the base station device 200 is an eNode B in a communicationsystem conforming to LTE, or a gNodeB in the 5G communication standard,for example. Note that a plurality of base station devices 200 may beincluded in the wireless communication system 10.

Upon receiving data to be transmitted to the terminal device 100-1, forexample, the base station device 200 allocates wireless resources to theterminal device 100-1, and transmits data to the terminal device 100-1using the allocated wireless resources.

The base station device 200 uses signals for data transmission (datatransmission signals) such as PDSCH (Physical Downlink Shared Channel)for example, to transmit downlink (from the base station device 200 tothe terminal device 100) data. The base station device 200 alsotransmits downlink control information (DCI: Downlink ControlInformation) to the terminal device 100 using control signals fortransmitting control information for wireless communication such asPDCCH (Physical Downlink Control Channel) for example. Downlink controlinformation includes information relating to the frequency band andtransmission timing (transmission start time, transmission time) and soforth of the PDSCH to be used, for example.

The terminal device 100 recognizes the frequency band and transmissiontiming of the PDSCH where the downlink data will be transmitted, byhaving received the above-described PDCCH, and can receive the downlinkdata by standing by for and receiving in this frequency band at thistransmission timing.

Data is retransmitted in accordance with the situation of wirelesscommunication, for example, in the wireless communication system 10according to the first embodiment. The base station device 200 transmitsthe retransmission data information regarding the frequency band andtransmission timing of retransmission data using PDCCH, of example. Theterminal device 100 can receive the retransmission data by receiving thePDCCH and recognizing the transmission timing and frequency band of theretransmission data.

Configuration Example of Base Station Device

FIG. 2 is a diagram illustrating a configuration example of the basestation device 200. The base station device 200 includes a CPU (CentralProcessing Unit) 210, storage 220, memory 230 such as DRAM (DynamicRandom Access Memory), an NIC (Network Interface Card) 240, and an RF(Radio Frequency) circuit 250.

The storage 220 is an auxiliary storage device such as flash memory, anHDD (Hard Disk Drive), an SSD (Solid State Drive), or the like, thatstores programs and data. The storage 220 has a wireless communicationcontrol program 221 and a retransmission pattern table 222.

The retransmission pattern table 222 is a table that stores informationregarding retransmission patterns, which will be described in detaillater. Note that the base station device 200 may store informationstored in the retransmission pattern table 222 as part of a program.

The memory 230 is a region where programs stored in the storage 220 areloaded. The memory 230 is also used as a region where programs storedata.

The NIC 240 is a network interface that connects to an external network,for example. The base station device 200 relays communication of theterminal device 100 by performing transmission/reception of packets withother communication devices and external networks via the NIC 240.

The RF circuit 250 is a device that performs wireless communication(wireless connection) with the terminal device 100. The RF circuit 250has an antenna 251 for example, and receives signals transmitted by theterminal device 100, and transmits signals to the terminal device 100.

The CPU 210 is a processor that loads programs stored in the storage 220to the memory 230, executes the loaded programs, and realizes eachprocessing.

The CPU 210 executes the wireless communication control program 221,thereby constructing a deciding unit (a deciding controller) and atransmission unit (a transmitter), and performing wireless communicationcontrol processing. The wireless communication control processing isprocessing of controlling wireless communication of the base stationdevice 200 and the terminal device 100.

The CPU 210 also performs wireless resource management processing byexecuting a wireless resource management module 2221 that the wirelesscommunication control program 221 has. The wireless resource managementprocessing is processing of allocating wireless resources used forwireless communication to each of the plurality of terminal devices 100,and managing the allocated wireless resources.

The CPU 210 also executes a retransmission pattern deciding module 2222that the wireless communication control program 221 has, therebyconstructing a deciding unit and performing retransmission patterndeciding processing. The retransmission pattern deciding processing isprocessing of deciding retransmission patterns in accordance with thecommunication state of wireless communication, or the allocationsituation of wireless resources to other terminal devices 100, forexample.

The CPU 210 also executes a data transmission module 2223 that thewireless communication control program 221 has, thereby constructing atransmission unit and performing data transmission processing. The datatransmission processing is processing of wirelessly transmitting data tothe terminal device 100. The base station device 200 retransmits data inthe data transmission processing, in accordance with the retransmissionpattern decided in the retransmission pattern deciding processing.

Configuration Example of Terminal Device

FIG. 3 is a diagram illustrating a configuration example of the terminaldevice 100. The terminal device 100 includes a CPU 110, storage 120,memory 130 such as DRAM, and an RF circuit 150.

The storage 120 is an auxiliary storage device such as flash memory, anHDD, an SSD, or the like, that stores programs and data. The storage 120has a wireless communication program 121 and the retransmission patterntable 222.

The memory 130 is a region where programs stored in the storage 120 areloaded. The memory 130 is also used as a region where programs storedata.

The RF circuit 150 is a device that performs wireless communication withthe base station device 200. The RF circuit 150 has an antenna 151 forexample, and receives signals transmitted by the base station device200, and transmits signals to the base station device 200.

The CPU 110 is a processor that loads programs stored in the storage 120to the memory 130, executes the loaded programs, and realizes eachprocessing.

The CPU 110 executes the wireless communication program 121, therebyconstructing an acquisition unit (an acquirer) and a reception unit (areceptor), and performing wireless communication processing. Thewireless communication processing is processing of wirelesslycommunicating with the base station device 200.

The CPU 110 also executes a retransmission pattern acquisition module1211 that the wireless communication program 121 has, therebyconstructing an acquisition unit, and performing retransmission patternacquisition processing. The retransmission pattern acquisitionprocessing is processing of acquiring a retransmission pattern from thebase station device 200.

The CPU 110 also executes a data reception module 1212 that the wirelesscommunication program 121 has, thereby constructing a reception unit,and performing data reception processing. The data reception processingis processing of receiving signals transmitted by the base stationdevice 200. The terminal device 100 receives retransmitted data in thedata reception processing, following a retransmission pattern acquiredin the retransmission pattern acquisition processing.

Data Transmission Processing

FIG. 4 is a diagram illustrating an example of data retransmission bythe base station device 200 in a simple retransmission format. Thesimple retransmission format is a format where control signals (e.g.,PDCCH) are given to signals transmitting data the first time, and allsignals where data is to be retransmitted, for example.

The base station device 200 has wireless resources of a predeterminedfrequency band and predetermined time. The base station device 200 usespart of the wireless resources for data transmission. In FIG. 4 , thebase station device 200 transmits signals SG1 including the PDCCHindicated by hatching and the PDSCH including the data to betransmitted, to the terminal device 100. The base station device 200then retransmits signals SG2 that includes the same data as the signalsSG1 in a case where a negative response (NACK) has been received or apositive response (ACK) has not been received in a predetermined amountof time, for example. The signals SG2 include a PDSCH including the samedata as the data transmitted by signals SG1, and a PDCCH includinginformation relating to the PDSCH to be retransmitted.

FIG. 5 is a diagram illustrating an example of data retransmission tothe terminal device 100-1 in the simple retransmission format. The basestation device 200 performs retransmission of data by the signals SG2 inthe same way as in FIG. 4 . However, in a case where wireless resourcesof signals SG3 indicated by the dotted lines in FIG. 5 have beenallocated to the terminal device 100-2, wireless resources of thesignals SG2 and signals SG3 partially overlap, causing interference, andthe signals SG2 will not be able to be transmitted to the terminaldevice 100-1 without error. The base station device 200 is not able toallocate wireless resources for the signals SG2 to another terminaldevice 100, so that the above-described interference will not occur.Accordingly, wireless resources may not be able to be efficiently usedin the simple retransmission format in some cases.

Accordingly, in the first embodiment, the base station device 200performs data retransmission by a retransmission format where controlinformation is not transmitted in retransmission of data (hereinaftermay be referred to as new retransmission format).

Data Retransmission Processing According to New Retransmission Format

FIG. 6 is a diagram illustrating an example of a sequence in dataretransmission processing according to the new retransmission format.The terminal device 100-1 periodically, or in response to a request fromthe base station device 200, for example, measures a propagation channelfor wireless communication between the terminal device 100-1 and thebase station device 200, and transmits a propagation channel measurementresults report including the measurement results to the base stationdevice 200 (S100).

The terminal device 100 measures reception power and interference powerof signals transmitted from the base station device 200, whichrepresents the signal strength on the propagation channel, in themeasurement of the propagation channel, for example. The terminal device100 then includes the measured reception power and interference power inthe propagation channel measurement results report, which is thentransmitted to the base station device 200. Note that the terminaldevice 100 may calculate a SINR (signal-to-interference-plus-noiseratio) from the reception power and interference power, and include thecalculated SINR (interference rate) in the propagation channelmeasurement results report.

Upon receiving the propagation channel measurement results report, thebase station device 200 performs retransmission pattern decidingprocessing (S101).

FIG. 7 is a diagram illustrating an example of a processing flowchartfor the retransmission pattern deciding processing S101. The basestation device 200 decides a retransmission count in accordance with thepropagation channel measurement results (S101-1). The base stationdevice 200 classifies the quality of the radio waves into five levels(level 1 is the best quality radio waves, and level 5 is the poorestquality radio waves) in accordance with the SINR value, for example. Thebase station device 200 then sets the retransmission count to zero timesin a case of level 1 where the signal strength is the best, andthereafter the retransmission count is one in a case of level 2, theretransmission count is two in a case of level 3, the retransmissioncount is three in a case of level 4, and the retransmission count isfour in a case of level 5, for example.

The base station device 200 decides the retransmission pattern to usefrom the retransmission pattern of the retransmission count that hasbeen decided, on the basis of the state of wireless resource allocationand latency conditions in data transmission (S101-2).

FIG. 8 is a diagram illustrating an example of a retransmission patterntable. The retransmission pattern table is a table that storesinformation elements of “retransmission pattern No.”, “retransmissioncount”, “retransmission count (breakdown)”, and “retransmissioncharacteristics (by each retransmission count)”, for example.

The “retransmission pattern No.” indicates the No. of the retransmissionpattern. There are ten patterns for retransmission patterns, e.g.,retransmission patterns 0 through 9. Retransmission pattern 0 is aretransmission pattern where the retransmission count is zero times, andwhere retransmission is not performed, for example. Also for example,retransmission pattern 9 is a retransmission pattern where theretransmission count is three, and data retransmission is performedthree times (four times including the first transmission).

The “retransmission count (breakdown)” is information regarding thefrequency band and time (transmission timing) for signals to retransmitdata. “Same time, different frequency” indicates the retransmissioncount for retransmission at the same transmission timing and at adifferent frequency band from the signals transmitted the first time.“Different time, same frequency” indicates the retransmission count forretransmission at a different transmission timing and at the samefrequency band as the signals transmitted the first time. “Differenttime, different frequency” indicates the retransmission count forretransmission at a different transmission timing and a differentfrequency band from the signals transmitted the first time.

The “retransmission characteristics (by each transmission count)” isinformation indicating the characteristics of signals to retransmit databy each retransmission count. The “retransmission characteristics (byeach transmission count)” indicates, for example, difference infrequency band and transmission timing as to the signals the first time.The “retransmission characteristics (by each transmission count)” alsoindicates, for example, dividing into two signals where the frequencyband is not consecutive.

FIG. 9A to FIG. 9D are diagrams illustrating an example of aretransmission pattern where transmission timings and frequency bandsare changed to perform retransmission. Hereinafter, retransmission ofthe N'th (where N is an integer) time will be expressed as N+1'th timeof transmission. For example, transmission of a total of three times isperformed in a retransmission pattern where retransmission is performedtwo times.

FIG. 9A is a diagram illustrating an example of retransmission pattern0. The base station device 200 does not perform retransmission inretransmission pattern 0, and performs the first transmission by signalsSG01.

FIG. 9B is a diagram illustrating an example of retransmissionpattern 1. The base station device 200 performs the first transmissionby signals SG11 in retransmission pattern 1. The signals SG11 include aPDCCH including information relating to the retransmission pattern. Notethat a PDCCH including information relating to the retransmissionpattern (e.g., retransmission pattern No.) in the signals transmittedthe first time is transmitted, in the other retransmission patterns aswell. The base station device 200 includes retransmission data insignals SG12 temporally consecutive from the signals SG11 and using afrequency band that is lower than the frequency band of signals SG11 byFB, and performs data transmission of the second time.

FIG. 9C is a diagram illustrating an example of retransmission pattern3. The base station device 200 performs the first transmission bysignals SG31 in retransmission pattern 3. The base station device 200includes retransmission data in signals SG32 temporally consecutive fromthe signals SG31 and using a frequency band that is lower than thefrequency band of signals S31 by FB, and performs data transmission ofthe second time. The base station device 200 further includesretransmission data in signals SG33 temporally consecutive from thesignals SG32 and using a frequency band that is lower than the frequencyband of signals SG32 by FB, and performs data transmission of the thirdtime.

FIG. 9D is a diagram illustrating an example of retransmission pattern5. The base station device 200 performs the first transmission bysignals SG51 in retransmission pattern 5. The base station device 200includes retransmission data in signals SG52 temporally consecutive fromthe signals SG51 and using a frequency band that is lower than thefrequency band of signals SG51 by FB, and performs data transmission ofthe second time. The base station device 200 further includesretransmission data in signals SG53 temporally consecutive from thesignals SG52 and using a frequency band that is lower than the frequencyband of signals SG52 by FB, and performs data transmission of the thirdtime. The base station device 200 moreover includes retransmission datain signals SG54 temporally consecutive from the signals SG53 and using afrequency band that is lower than the frequency band of signals SG53 byFB, and performs data transmission of the fourth time. Note however,that in a case where the frequency band of the signals SG54 exceeds tolower limit of allocable wireless resources as illustrated in FIG. 9D, afrequency band for the portion exceeding the lower limit is allocatedfrom the uppermost frequency band of allocable wireless resources,thereby dividing into two frequency bands and transmitting, for example.

FIG. 10A to FIG. 10C are diagrams illustrating an example of aretransmission pattern where the frequency band is changed andretransmission is performed at the same transmission timing. FIG. 10A isa diagram illustrating an example of retransmission pattern 2. The basestation device 200 performs the first transmission by signals SG21 inretransmission pattern 2. The base station device 200 includesretransmission data in signals SG22 using a frequency band that is lowerthan the frequency band of signals SG21 by FA at the same transmissiontiming as signals SG21, and performs data transmission of the secondtime.

FIG. 10B is a diagram illustrating an example of retransmission pattern7. The base station device 200 performs the first transmission bysignals SG71 in retransmission pattern 7. The base station device 200also includes retransmission data in signals SG72 using a frequency bandthat is lower than the frequency band of signals SG71 by FA at the sametransmission timing as signals SG71, and performs data transmission ofthe second time. The base station device 200 further includesretransmission data in signals SG73 temporally consecutive from thesignals SG71 and using the same frequency band as signals SG71, andperforms data transmission of the third time. The base station device200 further includes retransmission data in signals SG74 temporallyconsecutive from the signals SG72 and using the same frequency band assignals SG72, and performs data transmission of the fourth time.

FIG. 10C is a diagram illustrating an example of retransmission pattern8. The base station device 200 performs the first transmission bysignals SG81 in retransmission pattern 8. The base station device 200also includes retransmission data in signals SG82 using a frequency bandthat is lower than the frequency band of signals SG81 by FA at the sametransmission timing as signals SG81, and performs data transmission ofthe second time. The base station device 200 further includesretransmission data in signals SG83 at a first time period after thesignals SG81 and using the same frequency band as signals SG81, andperforms data transmission of the third time. The base station device200 further includes retransmission data in signals SG84 at a first timeperiod after the signals SG82 and using the same frequency band assignals SG82, and performs data transmission of the fourth time. Thefirst time period is a time period of transmitting PDSCH once, or a timeperiod of one slot.

FIG. 11A to FIG. 11C are diagram illustrating examples of otherretransmission patterns. FIG. 11A is a diagram illustrating an exampleof retransmission pattern 4. The base station device 200 performs thefirst transmission by signals SG41 in retransmission pattern 4. The basestation device 200 includes retransmission data in signals SG42 using afrequency band that is lower than the frequency band of signals SG41 byFA at the same transmission timing as signals SG41, and performs datatransmission of the second time. The base station device 200 furtherincludes retransmission data in signals SG43 temporally consecutive fromthe signals SG41 and using a frequency band that is lower than thefrequency band of signals SG41 by FB, and performs data transmission ofthe third time.

FIG. 11B is a diagram illustrating an example of retransmission pattern6. Retransmission pattern 6 is a retransmission pattern where thetransmission time (time of starting transmission) of the third time inretransmission pattern 5 is not temporally consecutive from thetransmission of the second time, and transmission is performed after afirst time period. The base station device 200 performs the firsttransmission by signals SG61 in retransmission pattern 6. The basestation device 200 includes retransmission data in signals SG62temporally consecutive from the signals SG61 and using a frequency bandthat is lower than the frequency band of signals SG61 by FB, andperforms data transmission of the second time. The base station device200 further includes retransmission data in signals SG63 at the firsttime period after the signals SG62 and using a frequency band that islower than the frequency band of signals SG62 by FB, and performs datatransmission of the third time. The base station device 200 moreoverincludes retransmission data in signals SG64 temporally consecutive fromthe signals SG63 and using a frequency band that is lower than thefrequency band of signals SG63 by FB, and performs data transmission ofthe fourth time. In a case where the frequency band of the signals SG64exceeds to lower limit of allocable wireless resources, a frequency bandfor the portion exceeding the lower limit is allocated from theuppermost frequency band of allocable wireless resources, therebydividing into two frequency bands and transmitting.

FIG. 11C is a diagram illustrating an example of retransmission pattern9. Retransmission pattern 9 is a retransmission pattern where the thirdtransmission in retransmission pattern 8 is divided into two signals ofdifferent frequencies that are temporally consecutive, and transmitting.The base station device 200 performs the first transmission by signalsSG91 in retransmission pattern 9. The base station device 200 alsoincludes retransmission data in signals SG92 using a frequency band thatis lower than the frequency band of signals SG91 by FA at the sametransmission timing as signals SG91, and performs data transmission ofthe second time. The base station device 200 further uses signals SG93-1temporally consecutive from the signals SG91 and using part of the samefrequency band as signals SG91 (the upper half in FIG. 11A to FIG. 11C)and signals S93-2 temporally following the signals S93-1 and using partof the same frequency band as signals S91 not used by the signals S93-1,and performs transmission of the third time. The base station device 200further includes retransmission data in signals SG94 at a first timeperiod after the signals SG92 and using the same frequency band assignals SG92, and performs data transmission of the fourth time.

Note that in retransmission patterns 1, 3, 5, and 6, for example,consecutive frequency bands are used for transmission of the firsttransmission and retransmission, but transmission may be performed usinga plurality of non-continuous frequency bands. The frequency band forretransmission may be a frequency band that is higher than the frequencyband in the first transmission.

Returning to FIG. 7 , an example of a method for deciding theretransmission pattern at the base station device 200 will be described,with reference to the retransmission patterns in FIG. 8 through FIG.11C.

In processing S101-1, the base station device 200 decides theretransmission count to be one time, for example. The base stationdevice 200 decides retransmission pattern 1 where the retransmissioncount is one time, and retransmission pattern 2, to be candidates forthe retransmission pattern to be used.

In processing S101-2, the base station device 200 confirms the state ofwireless resources. The state of wireless resources indicates wirelessresources used by another terminal device 100-2, for example. The basestation device 200 excludes retransmission patterns where part or alloverlap between the wireless resources of signals to be retransmittedand wireless resources that have been decided to be used by, or maypossibly be used by another terminal device 100-2. In a case where thereis one retransmission pattern remaining without being excluded, the basestation device 200 decides the remaining retransmission pattern to bethe retransmission pattern to be used.

The base station device 200 may also decide the retransmission patternwhere retransmission ends the earliest to be the retransmission patternto be used. Retransmission that ends the earliest indicates that latencyof data transmission is a short time in a case of the terminal device100 acquiring data by retransmitted data. The base station device 200compares retransmission pattern 1 and retransmission pattern 2 forexample, and decides retransmission pattern 2 where retransmission endsearlier to be the retransmission pattern to be used.

Further, the base station device 200 may decide the retransmissionpattern to be used on the basis of latency conditions of data to betransmitted. Latency conditions are delay time permissible from thefirst data transmission till the terminal device 100 correctly receivesthis data, for example. Latency conditions are also is time permissiblefrom data reaching the base station device 200 till the terminal device100 correctly receives this data, for example.

Latency conditions are defined as, for example, urgency of data to betransmitted, and requisite conditions of the wireless communicationsystem 10. When assuming that the terminal device 100 will receive thelast-retransmitted data, the base station device 200 determines whetheror not latency conditions are satisfied. The base station device 200then decides a retransmission pattern that satisfies the latencyconditions as the retransmission pattern to be used.

The base station device 200 may combine two or all selections of theabove-described selection by state of wireless resources, selection bytime to retransmission ending, and selection by latency conditions. Thebase station device 200 may also decide a retransmission pattern byassigning an order of priority to each of these three selections.

Returning to the sequence in FIG. 6 , the base station device 200performs data transmission the first time, once an opportunity totransmit data to the terminal device 100-1 occurs (S102). The basestation device transmits control signals (e.g., PDCCH) in the datatransmission the first time. The PDCCH includes retransmission patterninformation including the retransmission pattern No., for example. Theretransmission pattern information may also include, for example, valuesof FA and FB used in the retransmission patterns, and predetermined time(time interval in a case where retransmission is not temporallyconsecutive). The base station device 200 includes data to betransmitted to the terminal device 100-1 in data signals (e.g., PDSCH)and transmits the data.

The terminal device 100 that has received the PDCCH performsretransmission pattern acquisition processing (S103). The retransmissionpattern acquisition processing is processing where the retransmissionpattern information is extracted from the PDCCH, and retransmission datais received in accordance with the retransmission pattern that the basestation device 200 has decided. Note that in a case of having receiveddata without error, the terminal device 100 may transmit an ACK to thebase station device 200 and not receive subsequent retransmission data.

The base station device 200 retransmits data by the retransmissionpattern that has been decided (S104). The base station device 200transmits data being retransmitted by PDSCH, and does not transmit aPDCCH. Note that in a case of having received an ACK beforeretransmitting data, the base station device 200 does not have toperform retransmission of data.

In the first embodiment, the base station device 200 retransmits data tothe terminal device 100 even without having received a NACK.Accordingly, the base station device 200 performs retransmission withoutawaiting reception of a NACK, and thus can retransmit data at an earlytime, whereby delay of data transmission can be suppressed.

Also, a PDCCH including a retransmission pattern is transmitted at thetime of data transmission the first time, and no PDCCH is transmitted atthe time of transmitting retransmission data, thereby enabling overheadof the terminal device 100 receiving a PDCCH in each retransmission tobe reduced.

Further, the base station device 200 decides retransmission patterns onthe basis of measurement results of the propagation channel betweenitself and the terminal device 100, and wireless resources allocated toother terminal devices 100. Accordingly, a retransmission pattern with ahigher probability of the retransmission data reaching the terminaldevice without error can be decided.

Second Embodiment

The retransmission pattern information included in a PDCCH is preferablyas small in volume as possible, in a case where the capacity ofinformation transmittable by PDCCH is small or the information to betransmitted by PDCCH is predetermined and the capacity of otherinformation that can be included is small, for example. Accordingly, ina second embodiment, the base station device 200 includes part or all ofretransmission pattern information in an RRC (Radio Resource Control)message that controls the wireless network, and transmits to theterminal device 100.

Data Retransmission Processing According to New Retransmission Format

FIG. 12 is a diagram illustrating an example of a sequence in dataretransmission processing according to the new retransmission format.The terminal device 100-1 transmits a propagation channel measurementresults report including measurement results to the base station device200 (S200).

Upon receiving the propagation channel measurement results, the basestation device 200 performs retransmission pattern candidate selectionprocessing (S201). The retransmission pattern candidate selectionprocessing S201 is processing of selecting one or a plurality ofcandidates for retransmission patterns to use with the terminal device100-1. For example, the retransmission count is decided in the same wayas in the processing 101-1 in FIG. 7 , and a retransmission pattern forthe decided retransmission count is selected as a candidate for theretransmission pattern to be used.

The base station device 200 transmits a retransmission patternnotification including the selected retransmission pattern to theterminal device 100-1 by RRC message (S202).

The terminal device 100-1 receives the retransmission patternnotification, and thereupon performs retransmission pattern controlprocessing (S203).

FIG. 13 is a diagram illustrating an example of a processing flowchartof the retransmission pattern control processing S203. The terminaldevice 100 acquires a retransmission pattern candidate from theretransmission pattern notification (S203-1). The terminal device 100then stands by to receive a PDCCH including the retransmission pattern(No in S203-2).

Upon having received the PDCCH (Yes in S203-2), the terminal device 100acquires the retransmission pattern to be used (S203-3). The terminaldevice 100 then receives the retransmission data in accordance with theretransmission pattern to be used (S203-4).

Returning to the sequence in FIG. 12 , the base station device 200performs retransmission pattern deciding processing, once an opportunityto transmit data to the terminal device 100-1 occurs (S204). Theretransmission pattern deciding processing S204 is processing ofdeciding a retransmission pattern to use from retransmission patterncandidates, and is the same processing as the processing 101-2 in FIG. 7, for example.

The base station device 200 includes the retransmission pattern that hasbeen decided in a PDCCH and transmits the data to the terminal device100-1 (S205). The base station device 200 includes data to betransmitted to the terminal device 100-1 in data signals (e.g., PDCCH)and transmits the data.

The terminal device 100-1 receives the PDCCH in the retransmissionpattern control processing S203, and thereupon acquires theretransmission pattern that has been decided (S203-2 in FIG. 13 ). Theterminal device 100-1 thereafter receives the retransmission data inaccordance with the retransmission pattern that has been decided (S203-3in FIG. 13 ).

The base station device 200 then retransmits the data by theretransmission pattern that has been decided (S206). The base stationdevice 200 does not transmit a PDCCH during retransmission.

Note that in a case of the base station device 200 notifying theterminal device 100-1 of the retransmission pattern using one bit of thePDCCH, for example, the processing is as follows.

The base station device 200 performs notification that retransmissionpattern candidates are, for example, retransmission patterns 1 and 2, inthe retransmission pattern notification. The terminal device 100-1recognizes that the retransmission pattern candidates are retransmissionpatterns 1 and 2.

In a case of having decided to use retransmission pattern 1 in theretransmission pattern deciding processing S204, the base station device200 sets the bit in the PDCCH indicating the retransmission pattern thathas been decided to “0”, and in a case of having decided to useretransmission pattern 2, sets this bit to “1”.

The terminal device 100-1 determines that, in a case where the bit is 0for example, the retransmission pattern to be used is the retransmissionpattern 1, which is the candidate retransmission pattern with thesmaller retransmission pattern No., and in a case where the bit is 1,determines that the retransmission pattern to be used is theretransmission pattern 2, which is the candidate retransmission patternwith the larger retransmission pattern No. Accordingly, the terminaldevice 100-1 can acquire the retransmission pattern that has beendecided even if the number of bits used in the PDCCH is one bit. Notethat the base station device 200 may decide the number of candidateretransmission patterns in accordance with the number of bits usable inthe PDCCH, such as the number of candidate retransmission patterns beingfour in a case where the number of bits that can be used in the PDCCH istwo bits, and so forth.

The number of bits indicating information regarding retransmissionpatterns in a PDCCH can be reduced in the second embodiment, bytransmitting candidate retransmission patterns by RRC message.

Further, the retransmission pattern table may be, for example, an MCS(Modulation and Coding Scheme), or a table where allocation contents ofwireless resources used for each transmission are combined. Using alower MCS in a case where the retransmission count is great is assumedin combinations of retransmission patterns and MCS, and accordingly thebase station device 200 may reduce control signals by eliminating, ornot storing in memory, combinations of retransmission patterns withgreat retransmission counts and a higher MCS, for example.

Third Embodiment

The base station device 200 may instruct the terminal device 100 toperform retransmission in uplink (from the terminal device 100 to thebase station device 200) communication as well, for example.

FIG. 14 is a diagram illustrating an example of a sequence of uplinkdata retransmission processing according to the new retransmissionformat. The terminal device 100-1 transmits a propagation channelmeasurement results report including measurement results to the basestation device 200 (S300).

Upon receiving the propagation channel measurement results, the basestation device 200 performs uplink retransmission pattern candidateselection processing (S301). The uplink retransmission pattern candidateselection processing S301 is processing of selecting one or a pluralityof candidates for retransmission patterns to use with the terminaldevice 100-1. For example, the retransmission count is decided in thesame way as in the processing 101-1 in FIG. 7 , and a retransmissionpattern for the decided retransmission count is selected as a candidatefor the retransmission pattern to be used.

The base station device 200 receives propagation channel measurementresults from the terminal device 100-1 in FIG. 14 . The terminal device100-1 measures signal strength of downlink signals, and accordingly thebase station device 200 selects candidates for uplink retransmissionpatterns assuming that downlink and uplink radio wave properties (e.g.,degree of interference and so forth) are equivalent, for example. Notethat the base station device 200 may measure uplink signal strength.

The base station device 200 transmits a candidate retransmission patternnotification including the selected retransmission pattern to theterminal device 100-1 by RRC message (S302).

The terminal device 100-1 receives the retransmission patternnotification, and thereupon performs uplink retransmission patternacquisition processing (S303). The terminal device 100-1 acquires theuplink retransmission pattern candidate in the uplink retransmissionpattern control processing S303.

The base station device 200 performs uplink retransmission patternselection processing, once an opportunity to transmit data to theterminal device 100-1 occurs (S304). The uplink retransmission patternselection processing S304 is processing of deciding a retransmissionpattern to use from retransmission pattern candidates, and is the sameprocessing as the processing 101-2 in FIG. 7 , for example.

The base station device 200 transmits the PDCCH including the uplinkretransmission pattern that has been decided to the terminal device100-1 (S305). The terminal device 100-1 receives the PDCCH in the uplinkretransmission pattern acquisition processing S303, and thereuponacquires the retransmission pattern that has been decided. The terminaldevice 100-1 thereafter performs data transmission (S306) and dataretransmission (S307) using a PUSCH (Physical Uplink Shared Channel) inaccordance with the retransmission pattern that has been decided.

The base station device 200 can also control uplink data retransmissionin the third embodiment.

Other Embodiments

The base station device 200 may change an RV (Redundancy Version)defined in HARQ (Hybrid-ARQ (Automatic repeat request)) each datatransmission, for example. Combining different RVs of the same transportblock at the receiving side enables greater gain to be obtained, anderror rate can be reduced.

According to an aspect, delay in data transmission can be suppressed.

All examples and conditional language provided herein are intended forthe pedagogical purposes of aiding the reader in understanding theinvention and the concepts contributed by the inventor to further theart, and are not to be construed as limitations to such specificallyrecited examples and conditions, nor does the organization of suchexamples in the specification relate to a showing of the superiority andinferiority of the invention. Although one or more embodiments of thepresent invention have been described in detail, it should be understoodthat the various changes, substitutions, and alterations could be madehereto without departing from the spirit and scope of the invention.

REFERENCE SIGNS LIST

-   -   10: Wireless communication system    -   100 Terminal device    -   110 CPU    -   120 Storage    -   121 Wireless communication program    -   130 Memory    -   150 RF circuit    -   151 Antenna    -   200 Base station device    -   210 CPU    -   220 Storage    -   221 Wireless communication control program    -   222 Retransmission pattern table    -   230 Memory    -   250 RF circuit    -   251 Antenna    -   1211 Retransmission pattern acquisition module    -   1212 Data reception module    -   2221 Wireless resource management module    -   2222 Retransmission pattern deciding module    -   2223 Data transmission module

What is claimed is:
 1. A base station device performing wirelesscommunication with a terminal device, the base station devicecomprising: a processor configured to determine, out of a plurality ofresource patterns including a first resource pattern including aplurality of resources that are consecutive in a time domain and asecond resource pattern including a plurality of resources that arenon-consecutive in the time domain, a resource pattern; a transmitterconfigured to transmit, to the terminal device, a control signal forwireless resource allocation control including resource patterninformation relating to the resource pattern; and a receiver configuredto receive initial-time transmission data and retransmission data, theinitial-time transmission data and the retransmission data beingtransmitted from the terminal device in accordance with the resourcepattern information, wherein the transmitter is further configured totransmit a RRC (Radio Resource Control) message including configurationinformation relating at least part of the plurality of resourcepatterns, wherein the RRC message is different from the control signal.2. The base station device according to claim 1, wherein the receiver isfurther configured to receive the initial-time transmission data in afirst time resource, and the retransmission data in a second timeresource different from the first time resource.
 3. The base stationdevice according to claim 1, wherein the receiver is further configuredto receive the initial-time transmission data in a first frequencyresource, and the retransmission data in a frequency resource differentfrom the frequency resource.
 4. The base station device according toclaim 1, wherein the processor is further configured to determine theresource pattern in accordance with a wireless communication state; thewireless communication state includes an interference rate indicating adegree of interference occurring in a signal that the terminal devicereceives from the base station device.
 5. The base station deviceaccording to claim 1, wherein the control signal is transmitted by PDCCH(Physical Downlink Control Channel); and the initial-time transmissiondata and the retransmission data are transmitted by PDSCH (PhysicalDownlink Shared Channel).
 6. The base station device according to claim1, wherein the control signal includes information relating the firsttime resource.
 7. The base station device according to claim 1, whereinthe resource pattern information is one bit information.
 8. The basestation device according to claim 1, wherein the plurality of resourcesof the first resource pattern are used by the initial-time transmissiondata and the retransmission data when the first resource pattern isdetermined as the resource pattern, and the plurality of resources ofthe second resource pattern are used by the initial-time transmissiondata and the retransmission data when the second resource pattern isdetermined as the resource pattern.
 9. A terminal device performingwireless communication with a network device, the terminal devicecomprising: a receiver r configured to receive, from the network device,a control signal for wireless resource allocation control includingresource pattern information relating to a resource pattern, theresource pattern being determined out of a plurality of resourcepatterns including a first resource pattern including a plurality ofresources that are consecutive in a time domain and a second resourcepattern including a plurality of resources that are non-consecutive inthe time domain; and a transmitter configured to transmit initial-timetransmission data and retransmission data in accordance with theresource pattern information, wherein the receiver is further configuredto receive a RRC (Radio Resource Control) message includingconfiguration information relating at least part of the plurality ofresource patterns, wherein the RRC message is different from the controlsignal.
 10. The terminal device according to claim 1, wherein thetransmitter is further configured to transmit the initial-timetransmission data in a first time resource, and the retransmission datain a second time resource different from the first time resource. 11.The terminal device according to claim 1, wherein the transmitter isfurther configured to transmit the initial-time transmission data in afirst frequency resource, and the retransmission data in a frequencyresource different from the frequency resource.
 12. The terminal deviceaccording to claim 1, wherein the control signal is transmitted by PDCCH(Physical Downlink Control Channel); and the initial-time transmissiondata and the retransmission data are transmitted by PDSCH (PhysicalDownlink Shared Channel).
 13. The terminal device according to claim 1,wherein the plurality of resources of the first resource pattern areused by the initial-time transmission data and the retransmission datawhen the first resource pattern is determined as the resource pattern,and the plurality of resources of the second resource pattern are usedby the initial-time transmission data and the retransmission data whenthe second resource pattern is determined as the resource pattern.
 14. Awireless communication system comprising: a base station; and a terminalconfigured to communicate with the base station, wherein the basestation is further configured to: transmit a RRC (Radio ResourceControl) message including configuration information relating at leastpart of a plurality of resource patterns, a plurality of resourcepatterns including a first resource pattern including a plurality ofresources that are consecutive in a time domain and a second resourcepattern including a plurality of resources that are non-consecutive inthe time domain determine, out of the plurality of resource patterns, aresource pattern, transmit, to the terminal device, a control signal forwireless resource allocation control including resource patterninformation relating to the resource pattern, and receive initial-timetransmission data and retransmission data, the initial-time transmissiondata and the retransmission data being transmitted from the terminaldevice in accordance with the resource pattern information, wherein theRRC message is different from the control signal.